United States Phone Number Format Guide

The North American Numbering Plan uses a three-digit area code, three-digit exchange, and four-digit subscriber number. US and Canada share country code +1.

Validate required state, character set, length, and syntax on the client, then repeat validation on the server. Preserve the original input and normalize into a separate field; never truncate local scripts, compound names, or leading zeroes to fit a single Western assumption.

This guide describes common formats rather than an official registry and cannot enumerate every exception. Generated output is for testing only, not delivery, calling, identity verification, or real account activity.